Moves shared history test helpers into util classes.

BUG=None

Review URL: https://codereview.chromium.org/1646893003

Cr-Commit-Position: refs/heads/master@{#372681}
diff --git a/components/history.gypi b/components/history.gypi
index 20f647c..88f1a12 100644
--- a/components/history.gypi
+++ b/components/history.gypi
@@ -188,6 +188,8 @@
         'history/core/test/history_client_fake_bookmarks.cc',
         'history/core/test/history_client_fake_bookmarks.h',
         'history/core/test/history_unittest_base.cc',
+        'history/core/test/history_service_test_util.cc',
+        'history/core/test/history_service_test_util.h',
         'history/core/test/history_unittest_base.h',
         'history/core/test/test_history_database.cc',
         'history/core/test/test_history_database.h',